In order to test the color vision of a person, ophthalmologist and optometrists often use Ishihara images, which images are named after their developer. These are patterns of colored dots, which are presented to the person being tested. If the person recognizes the patterns, the person being tested may lack color recognition in this area. The lack of color recognition is possible in various degrees and expressions. The most familiar expression is the red-green weakness in men. In order to be able to determine the exact extent of the color blindness, a plurality of Ishihara images are needed. At a time of testing, the course of testing, which has so far taken place, is thereby important and determines which images will be presented to the person being testing during the further course of testing. In order to be able to cover the entire spectrum of the possible color blindness, an ophthalmologist or an optometrist must therefore have available a plurality of Ishihara images. The images, which as a rule are collected in books, are however, expensive to purchase. It is furthermore complicated to manually select the images necessary for the respective next step of testing from the plurality of existing images.
An alternative to the printed Ishihara images would be, for example, dias of the Ishihara images, which would be projected onto a screen by a slide projector. However, even when using slide transparencies, the problem of the scope, the image collection or the unsatisfactory possibility of the control of the sequence of the color vision test would continue to exist.
Also, as an alternative, it would be conceivable to use a picture screen, such as a LCD picture screen or a classic tube screen. However, these would be too expensive in relationship to their purpose so that the use of a picture screen to data does not represent a satisfactory alternative to the printed Ishihara images.
A device of the above-mentioned type, however, is not limited to the production of Ishihara images. Rather any desired patterns can be created with such a device. These may also, in the case of one single light source, be timed patterns of signals from the light source.
The purpose of the invention is therefore to provide a technically simple and inexpensive method and a vision-testing device, with which multicolored patterns can be produced. Whereby, in particular, a quick flexible automatic change between the multicolored patterns is possible.